The invention relates to an exhaust-gas aftertreatment device for an internal combustion engine and to a method for heating an exhaust-gas aftertreatment device.
In modern exhaust-gas aftertreatment systems, it is conventional for multiple types of exhaust-gas aftertreatment elements, for example catalytic converters or particle filters, to be integrated into an exhaust tract and for a targeted reduction of individual pollutant types to be sought by the exhaust-gas aftertreatment elements. Some of the exhaust-gas aftertreatment elements however attain their full performance or their optimum working temperature only when the internal combustion engine has warmed up. For this reason, extensive measures are implemented which ensure rapid heating of the exhaust-gas aftertreatment elements in the cold-start phase of an internal combustion engine.
From DE 198 00 654 A1, for example, it is known for a first water trap, an electrically heatable honeycomb body, a honeycomb body with catalytically active coating and a second water trap to be arranged in series in the exhaust-gas flow direction in an exhaust tract for an internal combustion engine. The electrically heatable honeycomb body and the honeycomb body with catalytically active coating may in this case preferably form a structural unit, whereby the honeycomb body with catalytically active coating can be heated more quickly by the electrically heatable honeycomb body in the cold-start phase of the internal combustion engine. In this way, the reduction of the pollutants in the exhaust gas of the internal combustion engine is improved. The two water traps further ensure that the two honeycomb bodies are in a dry state and thus warm up particularly rapidly.